The present invention relates generally to an electrical connector or socket for a pin grid array package.
Typically, an electrical connector for a pin grid array (xe2x80x9cPGAxe2x80x9d) package comprises a base housing for mounting a plurality of terminals in grid array fashion, and a slide plate formed with through holes in grid array fashion corresponding to the respective terminals and overlaid on the interior side of the base housing. The slide plate is adapted for sliding between a first insertion position and a second engagement position. In the first insertion position, the pins of the PGA package can be inserted adjacent to, but without engaging, the respective terminals with relatively small or zero insertion force. In the second engagement position, the pins are engaged with the respective terminals.
Sliding means or actuators for the slide plate are well known. One type of previously published sliding means includes a cam shaft mounted along the rear edge of the base housing to pivot the cam shaft by an operating handle provided along the side portion of the electrical connector. See Japanese Unexamined Patent Publication (Kokai) No. Heisei 7-142134. Another published sliding means includes a cam member inserted through the base housing and the slideplate and rotated by means of a flat bladed tool such as a screw driver. See U.S. Pat. No. 6,116,936.
However, the type of sliding means in which the cam member is inserted through the base housing and the slide plate is susceptible to a problem known as xe2x80x9ckickback.xe2x80x9d More specifically, when the slide plate is in the second engagement position, a force due to the resilience of the terminals tends to urge the slide plate away from the base housing and, thereby, to extract the cam member from its proper position with respect to the base housing. Also, the kickback force tends to move the slide plate back towards the first insertion position, thereby make the engagement between the pins and the respective terminals relatively less stable. Accordingly, despite the impressive achievements of earlier inventors, there still exists a need for an improved electrical connector.
The present invention includes a cam member having engaging means which rotatably engage the base housing. Said engaging means resist the tendency of kickback force to extract the cam member from its proper operating position. Additionally, the present invention may include a cam member having a cam surface which includes a flat wall. When the slide plate is in a pre-determined position, the flat wall abuts a cam opening having an inside surface which includes a straight edge. The flat wall in acts on cooperation with the straight edge to resist the tendency of kickback force to move the slide plate way from the first insertion position or the second engagement position
In a preferred aspect, the invention is an electrical connector for a pin grid array package which includes a generally planar base housing. The base housing has an exterior side which faces outwardly from the electrical connector and an interior side which faces in the opposite direction from the exterior side. The interior side includes a generally cylindrically shaped protuberance which extends in a direction generally transversely from the interior side. The base housing also defines a passage which extends axially through the protuberance from the interior side to a point adjacent the exterior side. Terminals are mounted on the base housing in an array which generally corresponds to the array of the pin grid package.
The electrical connector also includes a generally planar slide plate which defines a cam opening having an inside surface and through holes corresponding to the terminals. The side plate is disposed adjacent the interior side of the base housing, and is slidably movable between a first insertion position and a second engagement position. In the first insertion position, a lead pin of the pin grid array package can be inserted into a mounting portion adjacent at least one of the terminals. In the second engagement position, the lead pin is engaged with at least one of the terminals
The electrical connector additionally includes an eccentric cam member including a cam portion which defines a cam surface, a barrel which defines a bearing bore, an engaging leg which extends within and generally along the axis of the bearing bore, and engaging means for engaging the bearing bore or the exterior side. Said engaging means is mounted on the engaging leg. The cam member projects into the cam opening so that the cam surface is adjacent the inside surface. The protuberance projects into the bearing bore to rotatably support the cam member. The engaging leg projects into the passage. Said engaging means engages the barrel or the exterior side to resist axial movement of the cam member relative to the bearing bore.
Preferably, the engaging leg is strained within the barrel so as to urge said engaging means into engagement with the barrel or the exterior side of the slide plate. Preferably, said engaging means includes a hook mounted on the engagement leg and a step defined by the barrel adjacent the bearing bore.